Semi-Slav Defence

1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 e6

Hold d5 with two pawns, ...c6 and ...e6, so nothing White does in the centre ever quite works. Then the wall turns into a wave: you take on c4, chase the bishop with ...b5, and open your own bishop on b7 while White is still wondering what happened.

Spar this opening

Your setup

Knightf6
Knightd7
Bishopb7 / f5
Bishopd6 / e7 / b4
Queenc7 / b6
Pawnsc6 e6
CastleO-O

dxc4 before b5. Take on c4 first, then play ...b5. The other way round the c4-pawn is still on the board: cxb5 cxb5 and Bxb5+ picks up your pawn with check.

Ideas

Two pawns hold d5

...c6 and ...e6 both guard d5. White cannot win the centre by force.

The Queen's Gambit is an attack on d5. You answer by defending it twice with pawns, so that cxd5 always has a recapture and e4 never comes for free. The cost is a shut-in bishop on c8, and the rest of the opening is about letting it out.

Take on c4 once the bishop has moved

Wait for Bd3, then ...dxc4. The bishop moves again and you gain time.

If you take before the bishop has moved, Bxc4 develops it in one move. If you wait until it stands on d3, it has to capture on c4 and then run from ...b5, three moves for one piece. Patience here is worth a whole tempo.

The ...b5 wave

After Bxc4, ...b5 hits the bishop and claims the queenside.

This is the Meran signature. The pawn gains space, kicks the bishop for a second time, and prepares ...Bb7 and ...a6. Your whole queenside starts moving while White's bishop is still looking for a home.

...c5 frees everything

Once ...a6 guards b5, ...c5 opens the position for your bishops.

The c6-pawn has done its job holding d5. Moving it to c5 hits d4, opens the b7-bishop's diagonal, and gives your queen the c-file. But it also stops defending b5, so play ...a6 first: without it, Bxb5 just takes the pawn.

Against Bg5: take the pawn

5.Bg5 dxc4, then ...b5 to keep it. Expect a wild game.

With the bishop on g5 rather than e3, White cannot recapture on c4 quickly, so you take and hold with ...b5. White will throw e4 and e5 at you and the position gets sharp fast. If that is not your idea of fun, 5...h6 asks the bishop to decide first and is far calmer.

Against cxd5: mirror and get the bishop out

...cxd5, then ...Nf6, ...Nc6 and ...Bf5 before ...e6.

When White trades on d5 early, your c-pawn recaptures and the position becomes symmetrical. The one thing to get right is the light bishop: with the c-pawn gone it can come to f5 straight away, so do that before you play ...e6 and shut it in.

When the book runs out

Castle, put the queen on c7, and race your queenside against White's centre.

Your trumps are the b7-bishop and the queenside pawns; White's is the centre. Get castled, keep the c-file for your queen and rook, and push ...c5 or ...c4 when your pieces are ready. Do not open the centre yourself while your king is still on e8.

The structure

The Meran picture: two pawns have held d5, ...b5 chases the bishop, and the c-pawn is about to break to c5 and open the b7-bishop.

Traps

...b5 before ...dxc4

d4 d5 c4 c6 Nf3 Nf6 Nc3 e6 e3 b5 cxb5 cxb5 Bxb5+

The tell: You want the Meran's ...b5 and the c4-pawn is still on the board.

With c4 still there, cxb5 cxb5 opens the f1–b5 diagonal and the bishop takes on b5 with check. The order is fixed: take on c4 first, and only then ...b5 hits a bishop instead of losing a pawn.

...c5 before ...a6

d4 d5 c4 c6 Nf3 Nf6 Nc3 e6 e3 Nbd7 Bd3 dxc4 Bxc4 b5 Bd3 c5 Bxb5

The tell: Your pieces are ready for the ...c5 break and the a-pawn is still on a7.

The c6-pawn was the only thing guarding b5. The moment it moves, Bxb5 takes a free pawn. One quiet move, ...a6, makes the break safe.

Castling into a loose bishop

d4 d5 c4 c6 Nf3 Nf6 Nc3 e6 e3 Nbd7 Bd3 dxc4 Bxc4 b5 O-O bxc4

The tell: White has recaptured on c4 and reaches for the king instead of the bishop.

...b5 attacks the bishop and it must move. Players under 1200 often castle on autopilot here. Take it: a full bishop for nothing.

Model games

Meran main line

d4 d5 c4 c6 Nf3 Nf6 Nc3 e6 e3 Nbd7 Bd3 dxc4 Bxc4 b5 Bd3 Bb7 O-O a6 e4 c5 d5 c4 Bc2 Qc7

The whole plan: the wall on c6 and e6, ...dxc4 once the bishop commits, ...b5 and ...Bb7, ...a6 to guard, then ...c5 to free everything. When White pushes d5, ...c4 and ...Qc7 keep the queenside rolling.

The Exchange: bishop out first

d4 d5 c4 c6 cxd5 cxd5 Nc3 Nf6 Nf3 Nc6 Bf4 Bf5 e3 e6 Bd3 Bxd3 Qxd3 Bd6

When White trades on d5 you mirror the setup and get the light bishop to f5 before ...e6. Trade it when White offers; then ...Bd6 challenges the other bishop and the position is level.

Botvinnik: holding the pawn

d4 d5 c4 c6 Nf3 Nf6 Nc3 e6 Bg5 dxc4 e4 b5 e5 h6 Bh4 g5 Nxg5 hxg5 Bxg5 Nbd7

Against 5.Bg5 you take on c4 and keep it with ...b5. White breaks with e5 and sacrifices a knight on g5 to keep the pin; Black gets three pawns for the piece and a wild game. Know that it exists, and choose 5...h6 if you would rather not.

How the coach grades a move

Every move you play gets one of six grades, from the engine’s view of the position, with the book’s verdict taking over when it is harsher. The sentence beside it is always the reason. Tap it for what the move did, why this opening wants it, and whether anything was better.

Best: Nothing better was available.
Good: Within a few percent of best. Noise at this depth.
Playable: A small real gap. The better move is named, play goes on.
Inaccuracy: Seven to twelve points of winning chances. The game stops to show you.
Mistake: Twelve or more, or a move the book warns against, or a broken order rule.
Blunder: Twenty-five or more. Usually material.

Catalogued as D43–D49 in the Encyclopaedia of Chess Openings, the reference index most databases sort by.